Maternal diabetes in pregnancy has previously been linked to an increased risk of ocular refractive errors (REs), including hypermetropia, myopia and astigmatism, in the offspring. This large, population-based study using Danish national registries sought to quantify this risk.
Out of 2 470 580 live births recorded between 1977 and 2016 in Denmark, 56 419 (2.3%) were exposed to maternal diabetes (type 1, type 2 or gestational) in utero, including 22 762 (0.9%) whose mothers had type 1 diabetes. During follow-up from birth to 25 years of age, 553 offspring of mothers with diabetes and 19 695 offspring of those without the condition were diagnosed with high RE (hazard ratio [HR], 1.39; 95% confidence interval [CI], 1.28–1.51).
The risk associated with maternal type 2 diabetes was higher than for type 1 diabetes (HR, 1.68 vs 1.32), and the children of mothers with diabetes complications (used as a marker of worse glycaemic control) had a significantly higher risk than those whose mothers had no such complications (HR, 2.05 vs 1.18).
Hypermetropia occurred more frequently in childhood, whilst myopia was more frequent in adolescence and young adulthood. Nonetheless, the increased risk of RE was observed in all age groups studied (<3 years, 4–15 years and 16–25 years).
Potential mechanisms explaining the increased risk of high RE include downstream effects of hyperglycaemia in the fetal circulation leading to osmotic pressure changes in the eye, as well as damage to the optic nerve and retina due to hyperglycaemia-induced inflammation and oxidative stress.
The authors conclude that although the overall increase in RE risk was relatively small at 39%, increased ophthalmological surveillance in young children exposed to maternal diabetes could have positive effects, given that many REs in young children are treatable. This could especially be the case in children whose mothers had diabetes complications in pregnancy.
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